GB2027159A

GB2027159A - Shock absorbing tension links

Info

Publication number: GB2027159A
Application number: GB7919076A
Authority: GB
Original assignee: TUENKERS GmbH
Current assignee: TUENKERS GmbH
Priority date: 1978-06-01
Filing date: 1979-05-31
Publication date: 1980-02-13
Also published as: NL7904006A; FR2427433A1; DE2823953A1; DE2823953C2; FR2427433B1; GB2027159B; NL178617C; JPS5549427A; NL178617B; JPS6031970B2; US4274761A

Description

1 GB 2 027 159 _A _ 1_

SPECIFICATION

Improvements in vibration dampers The invention relates to a vibration-damping suspension for vibratory heads or other vibrating devices or bodies.

Vibratory heads held on a crane, boom or a frame by means of cables or iron bearing rings, are used for driving in or withdrawing planks, piles, sheet piling or pipes or other parts in the construction of dykes and canals or in underground workings.

The vibration necessarily produced by vibratory heads is transmitted to a greater or lesser extent in a troublesome and disadvantageous manner to, inter alia the cable gear, the frame, the crane, the 80 boom and/or other parts and locations. This can cause vibration and impact of considerable force which, in turn, not only cause great stresses on the parts and members under consideration but also can produce a considerable amount of sound and 85 noise. These, and other shortcomings and disadvantages are unavoidable and are caused particularly by suspending and holding the vibratory heads by means of support rings, hooks or similar rigid bodies on the crane, boom, frame or other members. It has also transpired that the disadvantageous vibration, impact, stresses, production of noise and other troubles cannot be prevented by suspending the vibratory heads from the crane, boom or frame by means of conventional cables. This manner of suspending the vibratory heads unavoidably has a disadvantageous effect on the boom, crane or the frame and produces oscillations and movements which might possibly lead to damage or 6perating 100 troubles or even to the fracture or destruction of a part or several parts of the apparatus.

Vibratory heads having helical compression springs of steel for damping vibration are known.

'These constructions have, inter alia, the disadvantage that they are highly susceptible to trouble and produce a considerable amount of noise. Large dynamic forces occur during operation and unavoidably cause detrimental contact and violent impacts between the individual turns of the helical compression springs.

Furthermore, the complicated guides for the springs, which are necessarily associated with sliding friction, are disadvantageous and cause a great amount of wear and produce a considerable 11,5 amount of heat particularly at frequencies in the range of natural resonance. Furthermore, the inefficiency of such compression spring assemblies is very disadvantageous when the turns of the springs are fully compressed by the 120 tension required when drawing and the undesirable oscillations are not absorbed.

Furthermore, it is known to use rubber blocks of appropriate design instead of the helical springs in the vibratory heads. With the large shear stresses which occur, and the relatively large static initial stress, constructions having helical springs or rubber blocks must ensure satisfactory vibration damping.

With the necessarily large applied load, the vibratory head must be of very high construction, so that, disadvantageously, an abnormally large overall height and an extremely unfavourable over-all centre of gravity for the vibratory head ensue. In this case, during operation, there is a considerable risk of damage, buckling and/or.fracture of parts and locations of the vibratory head and/or the vibratory elements.

An object of the invention is to prevent the transmission of undesired or disadvantageous vibrations and movements of the vibratory heads or similar devices and bodies to specific parts and locations of the apparatus. The aim of the invention is to provide a vibration-damping suspension, holder or the like for the vibratory heads or for other vibrating or moving bodies.

In accordance with the invention, a vibrationdamping suspension, holder or the like for vibratory heads or other vibrating apparatuses or bodies comprises two support members arranged opposite one another in the direction of tension applied to the suspension, two guide and fixing members disposed radially of the support members, a deformable endless strap or four go coacting endless straps connecting each of the two support members to both guide and fixing members, and one or a plurality of damping bodies made from rubber or other material disposed between said guide and fixing m6mbers so as to extend transversely of the direction of tension, such that changes of distance between the support members owing to changes in tension vary the compression in force in the damping body or damping bodies and thereby vary the length of the latter.

Accordingly, one support mem, ber or plate of the suspension can be selectively secured to a crane, frame, boom, frame or the like, while the other supp ort member or plate holds the vibratory head or some other body intended for a like purpose. The weight of the vibratory head and the vibrations produced thereby correspondingly increase the distance between the support plates in the direction of tension. These changes in distance and the vibrations are transmitted as compressive forces by way of the endless strap br straps to the two guide and fixing members or plates and to the resilient damping body of rubber or other material which is arranged therebetween and transversely of the direction of tension. The vibrations caused by the load of the vibratory head or other body located on the lower support plate are largely or entirely absorbed in the manner described, so that no vibrations or movements, or only damped vibrations or movements, can be transmitted to the crane, boom, the frame or staging by way of the upper support plate. The susl5ension is constructed and arranged such that it continuously changes its shape under the action of the tensile and compressive forces occurring, and the endless one-part or multi-part strip allows the two guide and fixing plates to have corresponding freedom of movement transversely of the direction of tension. The guide and fixing 2 GB 2 027 159 A 2 plates are undisplaceably held on the endless strap or straps. The two support plates are also undisplaceably held on the endless strap or straps. A damping body or a number of damping bodies of corresponding construction and arrangement, and 70 made from rubber, plastics material or other resilient material can be located between the two guide and fixing plates. Advantageously, damping bodies made from rubber or a similar material operate soundlessly. They also reliably avoid disadvantageous "full compression- under large tensile forces when pulling.

Characteristically, the support plates and the guide and fixing plates are non-displaceably held on a single endless strap in the form of a cable, wire, strip or the like by means of clamping staples, retaining eyes, retaining rings, retaining hooks or means. Alternatively, the support plates and the guide and fixing plates can also be provided with bolts to which the four short endless straps, required to form the endless sling, are hinged. The support plates and the guide and fixing plates are thereby also held on the endless:

strap or straps in an undisplaceable manner.

The required position of the damping body transversely of the direction of tension can be ensured by special constructions and means on an between the guide and fixing plates. It is possible to use one damping body or a number of damping bodies. Advantageously, the damping body is in the form of a compression spring. It can be of cylindrical, conical, angular, or other configuration.

Known draw heads are normally provided with individual vibration damping. These damping devices provided in the draw heads do not meet the demands made on them. Furthermore, they are disadvantageous in that they increase the overall height and weight of the draw heads to a considerable extent. In contrast to this, the suspension in accordance with the invention renders it unnecessary to provide vibration damping in the draw heads, so that, advantageously, the vibrating heads can be manufactured and used with a smaller overall height and lighter weight.

The invention is further described, by way of example with reference to the drawings, in which- Figure 1 is a diagramatically sectioned elevation of a suspension having an endless sling 115 comprising one endless cable, and Figure 2 is a similar view of a suspension having an endless sling comprising four endless straps.

Referring to Figure 1, an endless sling 1 120 comprising an endless cable, strip, wire or the like strap 2 of steel, plastics material or other material holds two support plates 3 and 4 which are spaced apart and located opposite one another and which are undisplaceably held on the cable 2 125 by clamping staples, retaining eyes or the like 5 and 6 by a support shackle, hook or other structure 7 for suspension from a crane, frame, staging or other location intended for this purpose, while the other support plate 4 has a support 130 shackle, hook or the like 8 from which the joltrammer 10 (e.g. a vibrator pile driving head) or some other body provided for a like purpose is suspended by means of a suspension rope or other member 9. The support plates 3 and 4 are arranged opposite to one another in the direction of tension in the endless sling 1. Two guide and fixing plates 11 and 12 are located, transversely of the direction of tension, centrally between the two support plates and are secured to the endless sling 1 by means of clamping staples, retaining eyes or the like 13, 14 on the endless cable 2. The guida plates 11 and 12 have thrust plates 15 and 16 and are undisplaceably mounted on the cable 2 with a damping body 17 of rubber or plastics material extending between the thrust plate 15 of the guide or fixing plate 11 and the thrust plate or other construction 16 on the guide plate 12 such that the longitudinal axis of the damping body 17 lies transversely of the direction of tension. Tension applied between the shackles 7 and 8 due to the load to which the endless sling 1 is subjected imposes a compressive force in the damping body by way of the endless strap 2 by virtue of the change in shape of the sling 1. Variations in theload vary the distance between the support plates 3 and 4 and corresponding and resiliently vary the length of the damping body 17. It is advantageous that,- because of the change in shape of the endless sling 1, disadvantageous "full compression" of the damping body 17, even in the case of large tensile forces during drawing, is substantially avoided. A further advantage is the silent mode of operation which can be obtained by the damping body made from rubber or some other resilient plastics material.

Advantageously, the damping body 17 can be of one-piece or multi-piece construction. It can be of cylindrical or other configuration and, in comformity with the existing conditions, it can be made entirely or partially from solid or hollow material. For the purpose of accurately holding the damping body 17 in its correct position, and to guide and move the damping body 17, sliding sleeves 18 and 19 are located on and between the thrust plates 15 and 16 of the guide and fixing plates 11 and 12. Guide rods 20 and 21 are located within the sliding bushes and hold a centering plate or disc 22. The damping body 17 can be unreleasably or releasably attached to thb pressure plates 15 and 16. The support plates 3 and 4 are non-displaceably held on the strap 2.

In the embodiment illustrated in Figure 2, the endless sling I is formed by four endless straps 23,24,25 and 26 of equal length, each of which can comprise an endless cable, strap, wire or the like made from steel, plastics material or other material. Each strap 23 to 26 is a rope-like structure having an eye, thimble or the like 27 at each end.

In the arrangement shown in Figure 2, the four endless straps 23 to 26 have to be connected to the two support plates 28 and 29 and to the two guide and fixing plates 30 and 31 to form the endless sling 1 such that the support plate 28 is It 3 GB 2 027 159 A 3 located opposite the support plate 29 in the direction of tension. The two guide and fixing plates 30 and 31 are spaced apart opposite to one another between the two support plates 28, 29 transversely of the direction of tension. Two bolts or the like 32 for receiving the endless straps 23 to 26 are provided on each support plate 28 and 29 and on each guide and fixing plate 30 and 31. The eye or thimble 27 at one loop of each endless strap is pivoted to a bolt 32 of a support plate, and the eye or thimble 27 at the other loop of each endless strap is hinged to the corresponding bolt 37 of the adjacent guide and fixing plate.

A thrust plate or other construction 33 is 16 located on the guide and fixing 30, while the guide and fixing plate 31 is provided with a thrust plate or the like 34. A damping body 35, whose longitudinal axis lies transversely of the direction of tension, is held by and between the two thrust plates 33,34. Advantageously, the damping body 34 is made from rubber or plastics material. Advantageously, it can be in the form of a hollow cone. Alternatively, however, it is possible to use a damping body 35 of cylindrical, rectangular or other appropriate configuration. The damping body 35 can be of one-part or multi-part construction. It is advantageous to provide the thrust plates 33 and 34 with suitable recesses or other formations for receiving and holding the abutting ends of the damping body 34. In order to hold the two frusto- conical damping members. 3 5 90 of the illustrated embodiment in their correct positions, it is advantageous to arrange therebetween a one-piece or multi-piece base plate 36. The ends of the damping bodies 35 can be secured to the base plate 36 by vulcanisation or in some other manner.

In the manner already described above, the device is secured to the crane, staging, frame or other location provided for this purpose by means of the supports shackle 7, while the cable gear with the jolt-rammer 10 or other body is suspended from the support shackle 8. The distance between the two support shackles 7, 8 in the direction of tension is correspondingly varied by the load which is applied to the device. These 105 changes of length are transmitted as a compression force by way of the thrust plates 33, 34 to the damping member 35 lying transversely of the direction of tension and are absorbed thereby. The construction and arrangement of this 110 embodiment in accordance with the invention ensure silent and satisfactory operation even in the case of large tensile forces. The damping member 35 acting as a compression spring can also absorb maximum pressures.

The vibration-dam ping suspension in accordance with the invention renders it possible, in an advantageous manner, to construct and use a drawing head (e.g. a vibratory pile extractor) without individual vibration damping, since vibration is damped by the present device. Thus, the jolt-rammer can be of substantially lower construction and can be manufactured so as to be lighter in weight. The small overall height obtainable thereby with a relatively light weight is of particular advantage and offers possibilities of versatile application even under difficult conditions for the jolt-rammers and the suspension.-

Claims

1. A vib ratio n-dam ping suspension for vibrating heads or other vibrating apparatuses or bodies, comprising two support members arranged opposite one another in the direction of tension applied to the suspension, two guide and fixing members disposed radially of the support members, a deformaole endless strap or four coacting endless straps connecting each of the two support members to both guide and fixing members, and one or a plurality of damping bodies made from rubber or other material disposed between said guide and fixing members so as to extend transversely of the direction of tension, such that changes of distance between the support members owing to changes in tension vary the compression force in the damping body or damping bodies and thereby vary the length of the latter.

2. A vibration-da rn ping suspension as claimed in claim I in which the two oppositely located guide and fixing members serve to hold the damping body in its correct position.

3. A vibration-damping suspension as claimed in claim 1 or 2, in which the distance between the two support members and the distance between the two guide and fixing members are commonly variable in dependence upon load and in dependence upon one another. 100

4. A vibration-dam ping suspension as claimed in any of claims 1 to 3 which has four endless straps of equal length and equal strength, made from cable, wire, strip or other material.

5. A vibration-da m ping suspension as claimed in any of claims 1 to 4, in which each support member is held by two endless straps and each guide and fixing member is also held by two endless straps, such that the support straps are located opposite one another in the direction of tension and the guide and fixing members are located opposite to one another in a direction lying transversely of the direction of tension.

6. A vibration-da m ping suspension as claimed in any of claims 1 to 5, in which one loop of each of four endless straps is secured to a support member and the other loop of each of the four endless straps is connected to a guide and fastening plate.

7. A vibration-damping suspension as claimed 4 GB 2 027 159 A 4 in any of claims 1 to 3, in which the support member and the guide and fixing members have clamping staples, retaining rings, retaining hooks, retaining eyes or other constructions for securing them to the endless strap.

8. A vibration-da m ping suspension constructed substantially as herein described with reference to and as illustrated in the drawings.

Printed for Her Majestys Stationery Office by the Courier Press, Leamington Spa, 1980. Published by the Patent Office. 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.

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